PDA

View Full Version : 30/40 g protein per meal is a myth, but what's the truth?



DokterVet
11-26-2006, 02:26 PM
I've seen several articles proclaiming "you can only absorb 30/40 g of protein per meal/hour" to be a myth, but none of them that I have seen have provided an actual helpful guide to go by.

Has there been any research done to actually determine how much protein one can absorb? What do you all use? I usually don't go above 50 per meal, but I have no idea if I can go higher or if that is too high.

RedSpikeyThing
11-26-2006, 02:32 PM
Do a search. There is no limit.

DokterVet
11-26-2006, 02:33 PM
Has that been confirmed via experiments, or has there just been no limit established?

Lones Green
11-26-2006, 02:38 PM
Has that been confirmed via experiments, or has there just been no limit established?

i'm sure built has posted some research on this, use the search feature.

DokterVet
11-26-2006, 02:41 PM
I have tried searching, and I have read many articles/posts. None of them had much of a conclusion, other than 30/40 g is a myth.

deeder
11-26-2006, 02:45 PM
I have tried searching, and I have read many articles/posts. None of them had much of a conclusion, other than 30/40 g is a myth.

Well.. If that's the conclusion they are coming to then what's the problem? You don't agree and want sources that say it's true?

DokterVet
11-26-2006, 03:57 PM
I want to know what is true (based on scientific experiment), not just what is false.

Pup
11-26-2006, 04:05 PM
I want to know what is true (based on scientific experiment), not just what is false.

The problem is that you really cannot define in strict mathematical terms how much protein the body can absorb per meal. For one thing, you have the Thermic effect of Feeding issue (which varies b/w 5-15% depending on the protein type). Then you have the amount of lean body mass each person has, as with any macronutrient, size of the test subject has a lot to do with nutrient absorbtion. There are so many variables involved in determining nutrient utilization that even if you could determine how much protein can be absorbed, its not a number that will remain static.

DokterVet
11-26-2006, 04:34 PM
Surely someone could come up with an estimate, perhaps based on the LBM of the individual.

Davidelmo
11-26-2006, 04:44 PM
Plus, there's a huge discrepancy in what people think "absorbed" means.

I'm sure that some people are under the impression that all the protein is broken down into aminos which go straight into muscle.

Your body will absorb almost anything you eat unless you have some GI disorder that affects motility or maybe some sort of transporter deficiency (i.e. intrinsic factor autoantibodies would reduce the amount of Vit-B12 you absorb) or some other malabsorption issue.

I would say that you should eat protein at every meal and aim to make sure there are amino acids available all the time. However I wouldn't set an upper limit per meal because there are too many variables.

Stumprrp
11-26-2006, 04:46 PM
Personally i dont think you should stress it, a 12 oz steak alone has over 60 grams of protien and im certainly not eating half! bring on the 20!

Alex.V
11-26-2006, 10:00 PM
Surely someone could come up with an estimate, perhaps based on the LBM of the individual.

No. Not a chance. It's not the amount of protein that passes your lips, it's the rate of amino acid entry into the bloodstream that matters.

You want to know why there's no ballpark? Cool. Let's take an example.

For a given 180 pound, 15% bodyfat male, we'll say his BMR amounts to exactly 2100 calories to maintain weight. This is assuming low to no activity whatsoever. In a starved state, his gut would likely be somewhat atrophied, but we could still assume that were his GI tract devoid of all nutrients (which would likely require him to be long dead, since the bacteria in the gut provide some amino acids and other nutrients), he is in a state that allows maximum nutrient absorption. We'll also say he's completely healthy, and therefore has all the enzymes and bacteria needed to completely and quickly digest all protein that enters his gut at a constant rate. Again, impossible to determine since the enzyme levels and flora/fauna levels fluctuate so wildly depending on activity level, diet, overall health of the host (you), etc.

ANYWAY. So this dude could absorb simple amino acids at a rate of, say, number out of my ass, 2 grams a minute. Not bad. He takes 120 grams of amino acid pills, and absorbs them all in an hour. Sounds about right, given that those pills will probably take about five minutes to dissolve in solution, then another hour to interact with all the necessary enzymes.

Now, polypeptides found in, say, whey protein, are a little more complex, so these may take another hour or so to digest. However, in large amounts they will quickly start to overwhelm the digestive enzymes, so the process will become less efficient. 30 grams of whey could be completely digested in about an hour, then absorbed over 15 minutes. However, since the amino acids are absorbing while digesting, it'll all be over with in 65 minutes or so. However, 60-120 grams of whey might take three hours plus to digest because of enzyme bottlenecks, so we're talking close to 200 minutes for complete absorption. Again, caveat, numbers are out of my ass but likely proportionate.

Now, overly complex proteins like those found in casein, or any various complex enzymes or long functional proteins, may take hours to digest, even in small amounts, since they can agglomerate and need a lot of time to break down in layers. So 10 grams of casein may digest in 20 minutes, but 100 grams might take hours and hours to digest and absorb.

Throw in these variables:

1) There are other foods being consumed, further altering rate of digestion and rate of absorption through sheer volume of food digested, limited lining space for nutrient exchange, increased agglomerate of the food bolus, etc.

2) Activity levels can vary, altering rate of digestion and rate of nutrient absorption due to lowered gastric motility, decreased blood supply to gut, etc.

3) Hydration levels can vary, and lower water levels decrease the efficiency of nutrient exchange and enzyme activity.

4) Individual digestive enzyme levels are like fingerprints.... no two human beings are exactly alike.

5) Same goes for concentration of various GI flora and fauna.

6) Overall health can change, which, again, alters enzyme levels, blood concentrations of amino acids, gastric motility, etc., affecting protein breakdown, nutrient exchange, and speed of digestion respectively. (just for starters).

I'm sure I left some things off the list.

And this is for any 180 pound 15% bodyfat guy. Change any of those three descriptors, and you've just thrown all your calculations out the window. In fact, add in height and size of torso, because that can alter GI tract length.

So, if you want to try to make up some simple guidelines that can be used to calculate how much protein of which type you can/should eat at a single meal, go ahead. But chances are your calculations will be totally ****ed.



Everyone else, just eat your ****ing protein. If it's whey, eat less at a time, if it's steak, eat more. If you're big, eat a lot, if you're smaller, eat less.

There. There are some god damn guidelines for you.

1mmort4l
11-27-2006, 12:47 AM
No. Not a chance. It's not the amount of protein that passes your lips, it's the rate of amino acid entry into the bloodstream that matters.

You want to know why there's no ballpark? Cool. Let's take an example.

For a given 180 pound, 15% bodyfat male, we'll say his BMR amounts to exactly 2100 calories to maintain weight. This is assuming low to no activity whatsoever. In a starved state, his gut would likely be somewhat atrophied, but we could still assume that were his GI tract devoid of all nutrients (which would likely require him to be long dead, since the bacteria in the gut provide some amino acids and other nutrients), he is in a state that allows maximum nutrient absorption. We'll also say he's completely healthy, and therefore has all the enzymes and bacteria needed to completely and quickly digest all protein that enters his gut at a constant rate. Again, impossible to determine since the enzyme levels and flora/fauna levels fluctuate so wildly depending on activity level, diet, overall health of the host (you), etc.

ANYWAY. So this dude could absorb simple amino acids at a rate of, say, number out of my ass, 2 grams a minute. Not bad. He takes 120 grams of amino acid pills, and absorbs them all in an hour. Sounds about right, given that those pills will probably take about five minutes to dissolve in solution, then another hour to interact with all the necessary enzymes.

Now, polypeptides found in, say, whey protein, are a little more complex, so these may take another hour or so to digest. However, in large amounts they will quickly start to overwhelm the digestive enzymes, so the process will become less efficient. 30 grams of whey could be completely digested in about an hour, then absorbed over 15 minutes. However, since the amino acids are absorbing while digesting, it'll all be over with in 65 minutes or so. However, 60-120 grams of whey might take three hours plus to digest because of enzyme bottlenecks, so we're talking close to 200 minutes for complete absorption. Again, caveat, numbers are out of my ass but likely proportionate.

Now, overly complex proteins like those found in casein, or any various complex enzymes or long functional proteins, may take hours to digest, even in small amounts, since they can agglomerate and need a lot of time to break down in layers. So 10 grams of casein may digest in 20 minutes, but 100 grams might take hours and hours to digest and absorb.

Throw in these variables:

1) There are other foods being consumed, further altering rate of digestion and rate of absorption through sheer volume of food digested, limited lining space for nutrient exchange, increased agglomerate of the food bolus, etc.

2) Activity levels can vary, altering rate of digestion and rate of nutrient absorption due to lowered gastric motility, decreased blood supply to gut, etc.

3) Hydration levels can vary, and lower water levels decrease the efficiency of nutrient exchange and enzyme activity.

4) Individual digestive enzyme levels are like fingerprints.... no two human beings are exactly alike.

5) Same goes for concentration of various GI flora and fauna.

6) Overall health can change, which, again, alters enzyme levels, blood concentrations of amino acids, gastric motility, etc., affecting protein breakdown, nutrient exchange, and speed of digestion respectively. (just for starters).

I'm sure I left some things off the list.

And this is for any 180 pound 15% bodyfat guy. Change any of those three descriptors, and you've just thrown all your calculations out the window. In fact, add in height and size of torso, because that can alter GI tract length.

So, if you want to try to make up some simple guidelines that can be used to calculate how much protein of which type you can/should eat at a single meal, go ahead. But chances are your calculations will be totally ****ed.



Everyone else, just eat your ****ing protein. If it's whey, eat less at a time, if it's steak, eat more. If you're big, eat a lot, if you're smaller, eat less.

There. There are some god damn guidelines for you.

:zipit: :zipit:

Belial for President!! :clap:

Davidelmo
11-27-2006, 02:39 PM
Belial just owned this thread

sCaRz*Of*PaiN
11-27-2006, 02:51 PM
No. Not a chance. It's not the amount of protein that passes your lips, it's the rate of amino acid entry into the bloodstream that matters.

You want to know why there's no ballpark? Cool. Let's take an example.

For a given 180 pound, 15% bodyfat male, we'll say his BMR amounts to exactly 2100 calories to maintain weight. This is assuming low to no activity whatsoever. In a starved state, his gut would likely be somewhat atrophied, but we could still assume that were his GI tract devoid of all nutrients (which would likely require him to be long dead, since the bacteria in the gut provide some amino acids and other nutrients), he is in a state that allows maximum nutrient absorption. We'll also say he's completely healthy, and therefore has all the enzymes and bacteria needed to completely and quickly digest all protein that enters his gut at a constant rate. Again, impossible to determine since the enzyme levels and flora/fauna levels fluctuate so wildly depending on activity level, diet, overall health of the host (you), etc.

ANYWAY. So this dude could absorb simple amino acids at a rate of, say, number out of my ass, 2 grams a minute. Not bad. He takes 120 grams of amino acid pills, and absorbs them all in an hour. Sounds about right, given that those pills will probably take about five minutes to dissolve in solution, then another hour to interact with all the necessary enzymes.

Now, polypeptides found in, say, whey protein, are a little more complex, so these may take another hour or so to digest. However, in large amounts they will quickly start to overwhelm the digestive enzymes, so the process will become less efficient. 30 grams of whey could be completely digested in about an hour, then absorbed over 15 minutes. However, since the amino acids are absorbing while digesting, it'll all be over with in 65 minutes or so. However, 60-120 grams of whey might take three hours plus to digest because of enzyme bottlenecks, so we're talking close to 200 minutes for complete absorption. Again, caveat, numbers are out of my ass but likely proportionate.

Now, overly complex proteins like those found in casein, or any various complex enzymes or long functional proteins, may take hours to digest, even in small amounts, since they can agglomerate and need a lot of time to break down in layers. So 10 grams of casein may digest in 20 minutes, but 100 grams might take hours and hours to digest and absorb.

Throw in these variables:

1) There are other foods being consumed, further altering rate of digestion and rate of absorption through sheer volume of food digested, limited lining space for nutrient exchange, increased agglomerate of the food bolus, etc.

2) Activity levels can vary, altering rate of digestion and rate of nutrient absorption due to lowered gastric motility, decreased blood supply to gut, etc.

3) Hydration levels can vary, and lower water levels decrease the efficiency of nutrient exchange and enzyme activity.

4) Individual digestive enzyme levels are like fingerprints.... no two human beings are exactly alike.

5) Same goes for concentration of various GI flora and fauna.

6) Overall health can change, which, again, alters enzyme levels, blood concentrations of amino acids, gastric motility, etc., affecting protein breakdown, nutrient exchange, and speed of digestion respectively. (just for starters).

I'm sure I left some things off the list.

And this is for any 180 pound 15% bodyfat guy. Change any of those three descriptors, and you've just thrown all your calculations out the window. In fact, add in height and size of torso, because that can alter GI tract length.

So, if you want to try to make up some simple guidelines that can be used to calculate how much protein of which type you can/should eat at a single meal, go ahead. But chances are your calculations will be totally ****ed.



Everyone else, just eat your ****ing protein. If it's whey, eat less at a time, if it's steak, eat more. If you're big, eat a lot, if you're smaller, eat less.

There. There are some god damn guidelines for you.AHAHAHAHA!!

http://i12.tinypic.com/34zy9u0.gif

Well there you go. :thumbup:

Alex.V
11-09-2012, 07:20 AM
I love forklifts.

Falcon63
11-09-2012, 10:22 AM
If you want to absorb the most protein, the most important thing is to chew your food (and liquids!) VERY thoroughly to help digestion. And yes, I said even liquids. You "chew" them to activate the salivary glands, if I'm not mistaken.

Alex.V
11-09-2012, 02:37 PM
You don't- saliva release is governed primarily by the nervous system. All that the chewing motion does is temporarily accelerate the release of saliva by squeezing out whatever is being stored.

The primary enzyme found in saliva (amylase) doesn't really do anything to protein at all- it's used to break down glycosidic bonds. i.e. it converts starches to sugars.

No need to chew your liquids- very few fluids contain long chain carbohydrates, and amylase is produced further down by the pancreas anyway.

Moving right along...

BIG_BEAR
11-12-2012, 08:38 PM
lol, very hilarious and helpful thread....